Methods, devices, and systems for physical random access channel (PRACH) access. A WTRU transmits a message to a gNB. The message includes a PRACH preamble from a first set. The method also includes performing a hidden node detection procedure prior to a random access response (RAR) window. The RAR window corresponds to the transmitted message. The method also includes attempting to receive a RAR in response to the transmitted message, during the RAR window. The method also includes retransmitting the message to the gNB, including a PRACH preamble from a second set, if the RAR is not received during the RAR window and a hidden node is detected; and retransmitting the message to the gNB, including a PRACH preamble from the first set, if the RAR is not received during the RAR window and the hidden node is not detected.